Superior water-flooding process



Patented July 9, 1963 3,096,820 SUPERIOR WATER-FLOODING PROCESS George G. Bernard, Crystal Lake, 111., assignor to The Pure ()il Company, Chicago, ill., a corporation of The results are far superior to those obtained when using either surfactant alone, and to the additive results which would be expected from using the surfactants in sequence. Still further improvements in oil recoveries and in the permeability of the formation can be obtained by includ Nolonmwing Filed Nov 16 1959 No 852 D62 ing in the first quantity of iloodwater, in combination with Claims i l the fatty acid-diethauolamine condensation product, a

' small quantity of the diethanolamine salt of benzene sul- This invention relates to a method for producing infonic acid. The addition of the suifonic acid salt results creased quantities of oil from subterranean iormations in an improvement when the method of this invention is by the injection of surfactant-containing water into the carried out on some crude 0115. I formation. This invention is further directed to a supe- S 1111 altematlve method 05 P f rior water-flooding process whereby substantial increases a Small amount of the fatty flcld-dlflthaholamlne SuIIaC- in the intake capacities of water-injection wells as 1am a 0f the lk v P l/ alcohol Surfactant m y achieved. be added to the same quantity of floodwater. This al- It is recognized by the art that the addition of surfaceterhflhvfi meihod is p adapted to h in active materials to floodwater prior to injection into the Whlhh the P Y P p of the h' f 15 to improve formation makes possible the production of greater quan the f- 9 fates P the hi Wells, Iathfl tities of oil than can be obtained by the injection of than Increase q y of 011 removed from the plain water or brine. It is further known that surfacef y the fioodwateractive materials added to floodwater serve to increase the It 15 p h h that the fatty aclds with whlfih the permeability of the formation surrounding the injection ethanqlamme 15 chhdehsed he y hcldsfvhlclh well. The addition of various surfactant agents to flood- 060111 in coconut 9 A Surfactant of this composlhoh 15 water has therefore been proposed. marketed by Swift and Company under the name of has now been discovered that two particular types Solar CO. Preparation of this surfactant is described of surfactant agents, each of which individually is an P Example AS hQfOR Stated, excellent iioodwater additive, when used together in flood- It i Pfeferred ihstahcfis to Include wlth thfi fatty i ayater produce a synergistic result. Thus, unexpectedly acid-diethanolamine IOHdCHSHUOH PI'OdUCt asmall amount 5 large oil recoveries are obtained, and further, the perof the diethanolamine salt of benzene sulfonic acid. meability of the treated formation is improved by a factor Swlft and markets sultfactam mhmlre hohtalhfhg f as much as 4 times the improvement obtainable b about 75% coco fatty acid-diethanolarrune condensation using an equal quantity of either surfactant individually. P h h about 25% dlethanolamlhfi 0f henlfihe h is an object Of this invention to provide an i d suifonic acid under the trade name of Solar 25. The isosurfactant water-flood process for the recovery of oil octyl Phehyl p y ethanol, which 15 adfied t0 the f subterranean f r ti 5 second quantity of fioodwater, should contain 7 to 13 It is another object of this invention to provide an irnethylehh oxfde groups, d Preiemhly flomams 9 f 10 proved water-flood process by which the permeability of f l Qxlde P Tmoh X400 15 a commercially the formation in the zone surrounding a water-injection w mlxtj-lre of lsooctyh Phehyl P Y Y 6111311018 well is substantially improved during the water-injection havlhg 9 t 10 ethylene Oxide B P pmcew 40 The effectiveness of the method of this invention was The method f this invention consists f injecting a demonstrated by the followingexperimental procedure. quantity of floodwater containing a small concentration Aluhdufh'cores having PP W of about a a of a surfactant which is the condensation product of a pefmeablhty. P 250 mlnjdarcys Y Saturated h a fa y acid having 8 to 18 carbon atoms and diethanolbnne compnsmg 5% f Pf and 9 Calcium inc, and then injecting a quantity of fioodwater conchloride, and were driven to minimum brine saturation taming a small amount of an 91 polyetfler gicohol with one of several selected crude oils. The cores were surfactant of tha formula, then flooded with brine until oil production ceased, that is, until the cores became watered out. The watered out cores were then flooded with brine containing 0.01% of i the selected surfactants or sequentially with uantities of 5o q CHz-Z cflr lgw 0H brine containmg nrst one selected surfactant and then the t H: CH: other. In each case, the surfactant concentration in the bn'ne was 0.01%. Experimental results are set out in I wherein n is an integer in the range of 7 to 13, inclusive. Table I. i TABLE I Oil Satuon Satu- Initial Oil ration Alter ration Alter Oil Pro- Permea Satu- Water Surfactant duced by bllity Surfactant Crude Oil ration, Flood. Flood. Surfactant, Increase.

Percent Percent Percent Percent Percent Pore Vol. Pore Pore 0! Residual Volume Volume Triton X-ioo Pl tte West Texas.-. 78.0 24.1 222 7. 9 9 Solar 25 -..do 77.8 24. s 10. 4 5s 0 -9 Solar 25Trit0n .X-IOO .410 79. 5 29. 0 l. 0 96. 6 45 Triton X- McClosky 80.3 26.0 25.1 3.5 13 Solar 25 --.do 78.7 22.2 16.6 27.0 7 Solar 25Triton X-lOO lo. 79. 1 21. 5 6.3 74. 4 94 Triton X-100 Aux Vases 78. 4 25. 8 23. 5 a 9 42 Solar 25... do 79. 4 29. s 14. 2 52. a 36 Solar 25Triton Xano do 77. 3 24. 2 1a. e 43. s 124 Triton X-100 West Texas Sour 78.3 28.1 23.5 16.4 5 Solar 130.... do 73. o 21. 6 12.0 56. 5 -11 Solar C0-Trlton X-lOO do 77. 1 29.3 3. 9 86.7 116 Where a single surfactant is listed under the Surfactant" column heading, the flood was carried out using 1200 cc; of surfactant-brine solution. Where two surfactants are listed on the same line, 400 cc. of brine containing the first-named surfactant was first injected into the core, and was followed by 400 cc. of brine containing Triton X-l00. ineach case, the pore volume of the core was about 15 cc.

In the experiments set out in Table II Bcrea sandstone cores were used. Where two surfactants are listed on the same line in Table H, 0.005% of each of the two named surfactants, for a total surfactant concentration of 0.01%, was used. In each instance in Table II, 150 pore volumes of surfactant solution were injected.

TABLE II Pore Percent Surfactant Crude Oil Volumes Increase or Soluin Perticn meability Triton X-100 West Texas Sour. 150 38 Solar do 150 70 Solar 25 150 42 Solar C0+Triton X 150 18.: Solar 25+Trlton X-IOO do 150 100 Triton X-l00 Adena- 150 29 Solar C0 do 150 31 Solar 25 do 150 -4 Solar CO+Trlton X-i00 do 150 51. Solar 25+Iriton X-100 do 150 126 Triton X-l00 Bonanza 150 28 Solar 00 do 150 10 Solar 25 .do 150 14 Solar OO-j-Triton X-IOO d0 150 103 Solar 25%-Triton X-l00 -do 150 54 The data in Table I clearly establishes that outstanding improvements in both oil recovery and core permeability were obtained by using the same total surfactant concentration and following the method of this invention. Furthermore, these improved results were obtained by the injection of a smaller total quantity of floodwater, since 1200 cc. of the single surfactant solutions were injected and 400 cc. of each of two surfactant solutions were injected where two surfactants were used. The date of Table II clearly establish that improvements in core permeability are obtained when the injected surfactant solution contains both the fatty acid diethanolamine and alkaryl polyether alcohol surfactants. While the results obtained by mixing the surfactants in the same quantity of fioodwater are less startling than those obtained by using the sequential injection of 'two quantities of fioodwater, each quantity containing one of the two named surfactant classes, still the data of Table 11 show a substantial improvement over the use of a single surfactant alone.

Where two separate batches of surfactant-containing floodwater are to be sequentially injected, which is the preferred method of carrying out the process of this invention, surfactant concentrations of about 0.0001 to 0.100% in the floodwater are effective in both steps of the process, but concentrations of about 0.005 to 0.050% appear to be most economical. lhe quantities of surfactant-containing water injected do not appear to be critical to the success of the process, but because the restriction to water intake at an injection well has its greatest effect in the zone immediately surrounding the injection well,-

that is, up to about a radial distance of feet, it is preferred that the volumes of solutions injected be related to these zones. It is advantageous to inject first and second batches of surfactant-containing fioodwater, which batches have a volume equal to about 50 times the volume of the reservoir pores within a radius of about 5 feet from the injection well.

Where both surfactants are to be incorporated in the some batch of floodwater, surfactant concentrations totalling about 0.001 to 0.100% in the fioodwater are effective, but concentrations of about 0.005 to 0.050% appear to be the most economical. The two surfactants may be present in concentration ratios ranging from about to 4 1 to 1 to 10, but it is preferred to use ratios of about 2 to l to 1 to 2.

As a specific example of the method of this invention, a subterranean reservoir containing connate brine and crude oil is produced by injecting through an input well and into the formation 0.1 reservoir pore volume of floodwater in which is dissolved 0.01% by weight of the condensation product of coco fatty acids and diethanolamine, then injecting through the input well and into the formation an equal volume of fioodwater in which is dissolved 0.01% by weight of isooctyl phenyl nonaethoxy ethanol. Reservoir fluids are produced from the reservoir through an output well. After the injection of the second batch of floodwater is completed, a. third batch of floodwater identical with the first is then injected, and so forth, alternating the kinds of surfactant dissolved in the hoodwater batches until the water-tooil ratio at the producing well reaches an uneconomically high level, at which point the process is terminated.

As another example of the method of this invention, petroleum oil is produced from a subterranean reservoir by injecting through an input well and into the reservoir fioodwater in which is dissolved 0.005% by weight of a surfactant mixture of 75% condensation product of coco fatty acids and diethanolamine and 25% diethanolamine salt of benzene sulfonic acid; and 0.005% by weight of isooctyl phenyl decaethoxy ethanol. Reservoir fluids are produced from an output well until the water-to-oil ratio at the outputwell reaches an uneconomically high level. At this point, the production of oil and the injection of flood-water is terminated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In the recovery of petroleum oil from the subterranean formation by the injection of floodwater through an input well and into said formation and the production of oil from said formation through an output well, the improvement comprising incorporating in at least a portion of said floodwater condensation products of fatty acids and diethanolamine, wherein the fatty acids contain 8 to 18 carbon atoms, and incorporating in at least a portion of said fioodwater an alkaryl polyether alcohol of the formula wherein n is an integer in the range of 7 to 13, the concentration of the compounds in said floodwater being about 0.001 to 0.100% by weight.

2. A method according to claim 1 in which the firstnamed compounds and the second-named compounds are present in the same portions of the floodwater.

3. A method according to claim 2. in which said firstnamed and second-narned compounds are present in the floodwater in concentration ratios ranging from about 10:1 to 1:10.

4. A method according to claim 2 in which between 0.005 and 0.050% total weight of said compounds is incorporated in said floodwater.

5. A method according to claim 2 in which said firstnamed and second-named compounds are present in the fioodwater in concentration ratios ranging from about 2:1 to 1:2.

6. A method according to claim 2 in which a small quantity of the diethanolamine salt of benzene sulfonic' acid is incorporated in said fioodwater.

7. A method according to claim 1 in which a portion of floodwater containing said condensation products is injected before injection of floodwater containing said alkaryl polyether alcohol.

8. A method according to claim 7 in which between 0.005 and 0.05 0% by weight of the first-named compounds and between 0.005 and 0.050% by weight of the secondnamed compounds are incorporated in the floodwater.

9. A method according to claim 7 in which the volume of floodwater containing each of said compounds is equal to about 50 times the pore volume of that portion of said formation which lies within the radius of about 5 feet from said input well.

10. A method according to claim 9 in which the firstnamed portion of flood water contains a small amount of the diethanolamine salt of benzene sulfonic acid.

11. A method according to claim 1 in which said fatty acids are coco fatty acids.

References Cited in the file of this patent UNITED STATES PATENTS De Groote et a1 Feb. 25, 1941 Graham et al May 21, 1957 Garst July 30, 1957 Johnson Feb. 24, 1959 Martin et al. Mar. 3, 1959 OTHER REFERENCES McCutcheon: Surfactons Listed," Part 4, Soap and Chemical Specialties, p. 67, March 1958. 

1. IN THE RECOVERY OF THE PETROLEUM OIL FROM THE SUBTERRANEAN FORMATION BY THE INJECTION OF FLOODWATER THROUGGH AN INPUT WELL AND INTO SAID FORMATION AND THE PRODUCTION OF OIL FROM SAID FORMATION THROUGH AN OUTPUT WELL, THE IMPROVEMENT COMPRISING INCORPORATING IN AT LEAST A PORTION OF SAID FLOODWATER CONDENSATION PRODUCTS OF FATTY ACIDS AND DIETHANOLAMINE, WHEREIN THE FATTY ACIDS CONTAIN 8 TO 18 CARBON ATOMS, AND INCORPORATING IN AT LEAST A PORTION OF SAID FLOODWATER AN ALKARYL POLYETHER ALCOHOL OF THE FORMULA 